The present invention relates to an automobile having a film mounted to its painted surface for reducing solar radiation load yet allowing the paint's color to shine through the film.
Direct sunlight on a painted surface of an automobile or vehicle may cause drivers to use the air conditioning system and/or use the air conditioning system at a higher level. The reason is that the paint and the underlying panel (e.g., metallic panel) may behave as a black body absorbing infrared radiation and re-radiating the absorbed infrared radiation as heat into the automobile cabin. Unfortunately, as a result, the air conditioning system may consume a large percentage of energy expended by the automobile in light of its overall energy consumption. By way of example and not limitation, the air conditioning system of the automobile may consume approximately twenty percent (20%) to about sixty percent (60%) of the total amount of energy consumed by the automobile. As such, reducing the cooling needs may reduce total energy consumption by the automobile.
The California Air Resources Board (“CARB”) has been attempting to draft a “cool car standard” for vehicles which would come into effect sometime in the future. The standard would require that the paint of any newly produced car to have a solar reflectivity of greater than a certain level (e.g., 65%). Unfortunately, such cool car standard has been postponed since it is believed that the requirements cannot be met by paint manufacturers. Also, even if the standard could be met, eighty (80) % compliance is believed to take approximately fourteen (14) years to implement.
Several factors determine the comfort level within the cabin of the automobile. They include the cabin air temperature, air speed within the automobile cabin, humidity of the air within the automobile cabin and the amount of thermal radiation entering the automobile cabin. When the cabin air temperature is uncomfortably hot, the automobile occupants may turn on the air conditioning system to cool down the average air temperature. In this instance, the air conditioning unit consumes energy to reduce the air temperature of the automobile cabin. The automobile occupants may also turn on and/or increase fan speed to increase air speed of the air circulating within the automobile cabin. The fan consumes energy. The speed of air within the automobile cabin increases evaporation of moisture on the skin of the automobile occupants which cools the occupant's skin temperature.
While driving during the day, the automobile cabin is exposed to the solar radiation. A portion of the solar radiation is absorbed by the paint and heated. A portion of the solar radiation may be transmitted through the paint and absorbed by the metallic panel under the paint. The infrared radiation absorbed by the paint and the metallic panel heats up and re-radiates energy into the cabin of the automobile to thereby increase the average air temperature of the automobile cabin. Additionally, the re-radiated energy may be absorbed by the interior of the automobile cabin. As such, the interior of the automobile cabin may have a large amount of re-radiated infrared radiation being transmitted. Unfortunately, since the roof, interior and windows of the automobile cabin tend not to allow transmission of infrared radiation there through, the automobile cabin retains the infrared radiation and may have an air temperature greater than ambient air temperature.
Moreover, the re-radiated radiation may be transmitted through the air within the automobile cabin and be directly absorbed by the occupant's skin. This may cause the occupants to feel uncomfortably hot thereby encouraging use of the air conditioning system of the automobile even if the cabin air temperature is within a comfortable range. This may cause the occupant to turn on the air conditioning system and/or fan. Use of the air conditioning system and the fan both consume energy. Any reduction in the use of the air conditioning system and fan would also reduce the total amount of energy consumed by the automobile.
The human skin contains receptors that are sensitive to thermal radiation in the infrared range. When the automobile occupants are exposed to the re-radiated thermal radiation, the occupants may be uncomfortable even if the cabin air temperature is within a comfortable range. The occupants may resort to decreasing the average air temperature of the cabin and increasing the air speed of the fan system to counteract the discomfort caused by the reradiated thermal radiation, both of which consume increasing amounts of energy.
As such, there is a need in the art for an apparatus and method for reducing the need to use the air conditioning system and/or fan of the automobile and mitigating exposure to thermal radiation.